I don't know anything about "The Fault in Our Stars", so that wouldn't occur to me, but I don't think
Hazel Grace flows very well and
Grace is a filler middle name, the 2010s equivalent of
Ann or
Lynn in the 1950s. What about
Hazel Zoe? That was my grandmother's name. Of course, she was named when
Zoe was a very unusual name, rather than the popular one it is now, but at least
Zoe isn't fillerish as a middle name.